This paper focuses on the structural stiffness of bump foils which are used for compliant foil bearings with different heat treatments. After heat treatments in vacuum environments, the mechanical properties of the foil strips were tested, and the structural stiffness was estimated from the static load versus displacement curves obtained from the experiments. High cycle dynamic load tests were also applied to the bump foil under different cycle loads, and the shape of the foil was scanned after the tests to measure the height variation of the bumps. The results show that the modulus of elasticity and strength of Inconel X-750 strip with thickness of 0.1 mm after different treatments are lower than that with the thickness of 0.18 mm at room temperature. Moreover, the sample foil strips which have been treated with a lower solution anneal temperature at 980 °C (2 hrs) and precipitation heat treatment at 732 °C (16 hrs) have the largest modulus of elasticity and strength at room temperature. Therefore, heat treatments have a great influence on the structure stiffness of the bump foil. At last, the results of the high cycle dynamic load tests show that the bump foil with suitable heat treatment will have a good load capacity and stress-relaxation property.

References

References
1.
Heshmat
,
C. A.
, and
Heshmat
,
H.
,
1995
, “
An Analysis of Gas-Lubricated, Multi-Leaf Foil Journal Bearings With Backing Springs
,”
ASME J. Tribol.
,
117
(
3
), pp.
437
443
.
2.
DellaCorte
,
C.
,
2012
, “
Oil-Free Shaft Support System Rotor Dynamics: Past, Present and Future Challenges and Opportunities
,”
Mech. Syst. Signal Process.
,
29
, pp.
67
76
.
3.
Heshmat
,
H.
,
Walton
,
J. F.
, II
, and
Tomaszewski
,
M. J.
,
2005
, “
Demonstration of a Turbojet Engine Using an Air Foil Bearing
,”
ASME
Paper No. GT2005-68404.
4.
Radil
,
K. C.
, and
DellaCorte
,
C.
,
2009
, “
Foil Bearing Starting Considerations and Requirements for Rotorcraft Engine Applications
,”
65th American Helicopter Society International Annual Forum
,
Grapevine, TX
, May 27–29, Paper No. ARL-TR-4873.
5.
Wu
,
X. W.
,
Chandel
,
R. S.
,
Li
,
H.
,
Seow
,
H. P.
, and
Wu
,
S. C.
,
2000
, “
Induction Brazing of Inconel 718 to Inconel X-750 Using Ni–Cr–Si–B Amorphous Foil
,”
J. Mater. Process. Technol.
,
104
(
1–2
), pp.
34
43
.
6.
Ferreno
,
D.
,
Gorrochategui
,
I.
,
Sanchez
,
L.
, and
Gutierrez-Solana
,
F.
,
2004
, “
Optimisation of Heat Treatment for Improvement of IGSCC Properties of an X-750 Alloy
,”
Eng. Failure Anal.
,
11
(
5
), pp.
799
810
.
7.
Inconel Alloy X-750, Huntington Alloy Products Division
,
1970
,
Product Design Guide
,
The International Nickel Company
,
Huntington, WV
.
8.
Davis, J. R.
,
2000
,
ASM Specialty Handbook—Nickel, Cobalt and Their Alloys
,
ASM International
,
Materials Park, OH
.
9.
DellaCorte
,
C.
,
Radil
,
K. C.
,
Bruckner
,
R. J.
, and
Howard
,
S. A.
,
2008
, “
Design, Fabrication, and Performance of Open Source Generation I and II Compliant Hydrodynamic Gas Foil Bearings
,”
STLE Tribol. Trans.
,
51
(
3
), pp.
254
264
.
10.
Roger Ku
,
C.-P.
, and
Heshmat
,
H.
,
1993
, “
Compliant Foil Bearing Structural Stiffness Analysis-Part II: Experimental Investigation
,”
ASME J. Tribol.
,
115
(
3
), pp.
364
369
.
11.
Ruscitto
,
D.
,
McCormick
,
J.
, and
Gray
,
S.
,
1978
, “
Hydrodynamic Air Lubricated Compliant Surface Bearing for an Auto-Motive Gas Turbine Engine: I-Journal Bearing Performance
,” Report No. NASA CR–135368.
12.
Heshmat
,
H.
,
Shapiro
,
W.
, and
Gray
,
S.
,
1982
, “
Development of Foil Journal Bearings for High Load Capacity and High Speed Whirl Stability
,”
ASME J. Lubr. Technol.
,
104
(
2
), pp.
149
156
.
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